U.S. patent application number 10/231172 was filed with the patent office on 2003-04-03 for vehicle alternator having impact and vibration resistant terminal connection.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Matsubara, Shinichi, Murata, Nakato, Tan, Yoshiki.
Application Number | 20030062781 10/231172 |
Document ID | / |
Family ID | 19122414 |
Filed Date | 2003-04-03 |
United States Patent
Application |
20030062781 |
Kind Code |
A1 |
Murata, Nakato ; et
al. |
April 3, 2003 |
Vehicle alternator having impact and vibration resistant terminal
connection
Abstract
A vehicle alternator has an armature coil, a rectifier, and a
terminal connector. The armature coil has a substantial rectangular
cross-section. The rectifier rectifies a voltage induced at the
armature coil. The terminal connector includes a crimping portion
and a connecting portion. The crimping portion is crimped onto a
lead of the armature coil. The connecting portion is fixed to an
input terminal of the rectifier with a screw. The crimping portion
of the terminal connector is crimped onto the lead so that two
opposed surfaces of the lead have surface contact with the terminal
connector.
Inventors: |
Murata, Nakato;
(Nagoya-city, JP) ; Tan, Yoshiki; (Anjo-city,
JP) ; Matsubara, Shinichi; (Anjo-city, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
DENSO CORPORATION
kariya-city
JP
|
Family ID: |
19122414 |
Appl. No.: |
10/231172 |
Filed: |
August 30, 2002 |
Current U.S.
Class: |
310/71 |
Current CPC
Class: |
H02K 3/50 20130101 |
Class at
Publication: |
310/71 |
International
Class: |
H02K 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2001 |
JP |
2001-302105 |
Claims
What is claimed is:
1. A vehicle alternator comprising: a stator core; an armature coil
wound around the stator core and having a lead shaped in a
substantial rectangular cross-section; a rectifier for rectifying
an alternating current voltage induced at the armature coil to a
direct current voltage; and a terminal connector having a crimping
portion crimped exclusively onto the lead of the armature coil and
a connecting portion fixed to an input terminal of the rectifier,
wherein the lead has two pairs of opposed surfaces and one of the
pairs is in surface contact with the terminal connector.
2. The vehicle alternator as in claim 1, wherein the other pair of
opposed surfaces is away from the terminal connector to provide a
space for jointing material having electrical conductivity.
3. The vehicle alternator as in claim 1, wherein the crimping
portion includes a bottom portion in surface contact with one of
the opposed surfaces of the lead and claw portions extending from
both sides of the bottom portion.
4. The vehicle alternator as in claim 3, wherein one of the opposed
surfaces of the lead is plastically deformed.
5. The vehicle alternator as in claim 4, wherein: ends of the claw
portions face each other with a gap; and a part of the opposed
surface that is plastically deformed is placed in the gap.
6. The vehicle alternator as in claim 2, wherein the space in which
the lead is inserted has a substantial trapezoid cross-section.
7. The vehicle alternator as in claim 6, wherein a shorter base of
the substantial trapezoid cross-section and a part of the lead in
line contact with the shorter base are an approximately same
length.
8. The vehicle alternator as in claim 1, wherein: the armature coil
is constructed of substantial U-shaped segment conductors and
having a rectangular cross-section; the segment conductors are
connected to form multiple-phase windings and inserted in slots of
the stator core.
9. The vehicle alternator as in claim 1, wherein the opposed
surfaces are in direct surface contact with the terminal connector
over substantially entire areas thereof.
10. The vehicle alternator as in claim 2, wherein the space is
filled with jointing material having electrical conductivity.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on and incorporates herein by
reference Japanese Patent Application No. 2001-302105 filed on Sep.
28, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to a vehicle alternator having
impact and vibration resistant terminal connection.
BACKGROUND OF THE INVENTION
[0003] In a vehicle alternator, an AC voltage induced at an
armature coil is rectified to a DC voltage by a rectifier. The
armature coil and rectifier are connected by soldering, welding, or
utilizing a terminal connector attached to leads (lead-out wires)
of the armature coil.
[0004] A vehicle alternator having a terminal connector crimped
onto lead-out wires of armature coil is disclosed in U.S. Pat. No.
5,914,546 (JP-A-10-4646). Each lead-out wire has a round
cross-section and the terminal connector is crimped onto a
plurality of lead-out wires. Therefore, a contact area between each
lead-out wire and terminal connector is insufficient. To augment
electrical conductivity, solder or brazing filler metal is filled
in the space around the lead-out wire.
[0005] In recent years, vehicle engines are reduced in weight and
increased in power output. As a result, engines cause high
vibration, resulting in severe condition of space in which the
alternator is installed. Moreover, solder or brazing filler metal
deteriorates over time. This may cause poor electrical connection
between the lead-out wires and terminal.
[0006] The terminal connector requires space to provide the solder
or brazing filler metal around the lead-out wires inside the
crimping portion. Because of the space, the lead-out wire may not
be placed in a proper position for crimping when it is inserted in
the crimping portion. In such a case, the terminal connector is not
properly crimped onto the lead-out wire and insufficient electrical
connection may occur.
[0007] To counter the above problems, the lead-out wire may be
deformed to a rectangular cross-section when crimping the terminal
connector onto the wire. By deforming the lead-out wire to a
rectangular cross-section, sufficient contact area is provided.
However, this may cause broken wire because stress is applied to
the deformed area when vibration occurs. Therefore, this
alternative is not appropriate for practical application.
SUMMARY OF THE INVENTION
[0008] The present invention therefore has an objective to provide
a vehicle alternator in which contact failure minimally occurs even
under severe installation conditions.
[0009] A vehicle alternator of the present invention includes a
stator, a rectifier, and terminal connectors. The stator has a
stator core and an armature coil wound around the stator core. The
armature coil has a rectangular cross-section. The rectifier
converts an AC voltage induced at the armature coil to a DC
voltage. The terminal connector has a crimping portion and a
connecting portion. The crimping portion is used for crimping a
lead (lead-out wire) of the armature coil. The connecting portion
is connected to an input terminal of the rectifier with a
screw.
[0010] When the terminal connector is crimped onto the lead-out
wire, opposed surfaces of the lead-out wire have surface contact
with the crimping portion of the terminal connector. As a result,
sufficient contact area is provided with a minimal amount of
plastic deformation of the lead-out wire. This reduces the
occurrence of connection failures under the severe installation
condition. This also reduces an amount of solder or brazing filler
metal. The solder or brazing filler metal may not be needed if the
crimping portion is well designed so that the lead-out wire has
better surface contact with the terminal connector.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above and other objectives, features and advantages of
the present invention will become more apparent from the following
detailed description made with reference to the accompanying
drawings. In the drawings:
[0012] FIG. 1 is a cross-sectional view of an alternator according
to an embodiment of the present invention;
[0013] FIG. 2 is a plain view of a part of the stator according to
the embodiment;
[0014] FIG. 3 is a perspective view of a part of the stator
according to the embodiment;
[0015] FIG. 4 is a cross-sectional view of a lead-out wire on which
a terminal connector is crimped according to the embodiment;
[0016] FIG. 5 is a enlarged cross-sectional view of a part of the
alternator around the terminal connector according to the
embodiment;
[0017] FIG. 6 is a cross-sectional view of the lead-out wire on
which a modified terminal connector is crimped according to the
embodiment;
[0018] FIG. 7 is a cross-sectional view of the lead-out wire on
which a modified terminal connector is crimped; and
[0019] FIG. 8 is a cross-sectional view of the alternator having
the lead-out wire and terminal connector shown in FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] The preferred embodiment of the present invention will be
explained with reference to the accompanying drawings.
[0021] Referring to FIG. 1, an alternator 100 includes a frame 1, a
stator 2, a rotor shaft 3, a stationary yoke 4, a field coil 5, a
rotor core 6, bearings 8 and 9, and a rectifier 10.
[0022] The stator 2 includes a stator core 21 and an armature coil
7 wound around the stator core 21. The stator core 21 is made of
steel sheets and fixed to a cylindrical interior wall of the frame
1. A number of slots are provided on the interior wall of the
stator core 21 for receiving the armature coil 7 therein.
[0023] Referring to FIGS. 2 and 3, the armature coil 7 is
constructed of a plurality of U-shaped segment conductors 70. Each
U-shaped segment conductor 70 has a pair of straight portions 701
and a curved portion 702. Each straight portion 701 is inserted
into one of slots provided with a predetermined pitch in the stator
core 21. An end portion 704 of the segment conductor 70 is bent in
the circumferential direction to a specified position and connected
with an end portion 704 of other segment conductor 70 so that
three-phase windings are constructed.
[0024] A lead-out wire 73 is extended from the curved potion side
(right side in FIG. 2) of the stator 2 in parallel with the rotor
shaft 3 and connected to the rectifier 10. A terminal connector 74
is crimped onto the end of the lead-out wire 73. The lead-out wire
73 has a cross-sectional shape of rectangle as shown in FIG. 4. The
terminal connector 74 is crimped on the lead-out wire 73.
[0025] Referring to FIGS. 4 and 5, the terminal connector 74 has a
crimping portion 741 and a connecting portion 742. The connecting
portion 742 is fixed to the input terminal 24 with a screw 3101 via
a washer 3102. The crimping portion 741 is crimped onto the
lead-out wire 73. When the crimping is completed, the cross-section
of the crimping portion 741 becomes as shown in FIG. 4. The
cross-section is a trapezoid and the upper base is approximately
same length with the width of the lead-out wire 73. This enables
proper positioning of the lead-out wire 73 in the crimping portion
741.
[0026] The crimping portion 741 has a bottom portion 741a and claw
portions 741b and 741c. The claw portions 741b and 741c are bent
and a force is applied in the vertical direction of FIG. 4 so that
they are pressed against the top surface of the lead-out wire 73.
At the same time, the bottom portion 741a is pressed against the
bottom surface of the lead-out wire 73. As a result, both claw
portions 741b and 741c are in surface contact with the top surface
of the lead-out wire 73 and joined to each other at the same
time.
[0027] The crimping portion 741 and lead-out wire 73 have a
trapezoid cross-section and a rectangular cross-section,
respectively. Therefore, a space defined by the crimping portion
741 and lead-out wire 73 has a triangle cross section. This space
is referred to as a triangle space 75 in FIG. 4. By filling the
triangle space 75 with solder or brazing filler metal, electrical
contact resistance between the lead-out wire 73 and terminal
connector 74 can be reduced.
[0028] A modified terminal connector is shown in FIG. 6. A gap 743
is provided between two claw portions 741b and 741c. The lead-out
wire 73 is plastically deformed and a part of it is placed in the
gap 743 when bending the claw portions 741b and 741c for crimping.
This decreases a size of space between the lead-out wire 73 and
terminal connector 74. As a result, the contact resistance between
them can be reduced. Moreover, the lead-out wire 73 can be properly
positioned in the crimping portion 741 by placing a part of the
lead-out wire 73 in the gap 743. This ensures a stable connecting
condition.
[0029] Front coil end 71 and rear coil end 72 are constructed of
U-shaped segment conductors 70 as shown in FIGS. 2 and 3. The
straight portions 701 of the U-shaped segment conductors 70 are in
diagonal position relative to the circumference of the stator core
21 and parallel to each other. As a result, a number of air
passages 1000 in a cross-sectionally diamond shape are uniformly
formed in both the radial and axial directions. In the coil end 71,
the end portions 704 are extended in the axial direction so that
they are fixed to each other. As a result, radial directional air
passages 1001 are formed between the end portions 704. Each segment
conductor 70 never overlaps in the radial or axial direction.
Therefore, all segment conductors 70 can be cooled down with a
small loss of fluid resistance when ventilation is performed in the
radial or axial direction.
[0030] The rotor shaft 3 is supported by a front-end wall 11 via
the bearing 8 and by a rear-end wall 12 via the bearing 9. A pulley
(not shown) is fixed to the outside of the front-end wall 11 with a
nut.
[0031] The stationary yoke 4 is a cylinder-shaped soft iron core
that surrounds the rotor shaft 3 and fixed to the front-end wall 11
with a bolt 41. The stationary yoke 4 has a groove around its outer
wall near the front end. The field coil 5 is wound around the
stationary yoke 4 in the groove.
[0032] The rotor core 6, which is fixed to the rotor shaft 3,
provides a magnetic path for field flux along with the stationary
core 4. The rotor core 6 includes a pair of rotor yokes 61 and 62,
a plurality of first claw poles 63 and second claw poles 64, and a
supporting member 65. The rotor yokes 61 and 62 are placed closer
to each other in the axial direction and fixed to the rotor shaft
3. The claw poles 63 and 64 are integrated with the rotor yoke 62.
The supporting member 65 is a ring made of non-magnetic material.
The supporting member 65 is used for integration of the first and
second claw poles 63 and 64.
[0033] The rotor yoke 61 is a cylindrical-shaped soft iron core.
Its outer wall faces the inner wall of the stationary yoke 4 with a
small gap. The other rotor yoke 62 is also a cylindrical-shaped
soft iron core. The rotor yoke 62 has two portions, first core
portion 621 and second core portion 622. The first core portion 621
is located inside the stationary yoke 4 with a small gap in between
and its periphery faces the inner wall of the stationary yoke 4.
The second core portion 622 is located behind the first core
portion 621 and its diameter is larger than the interior diameter
of the stator yoke 4.
[0034] Each claw of the first claw poles 63 is extended from the
core portion 622 in the axial direction as if the claw is attached
to the outer wall of the rotor core 62. The claws, provided with
constant pitches in the circumferential direction, are inserted
into claw pole storing space defined by the inner wall of the
stator core 21 and the outer wall of the field winding 5. A cooling
fan 66, which generates cooling air flowing in the axial and
centrifugal directions, is fixed to the top of the rotor core 62.
The top of the rotor core 62 is positioned inwardly compared to the
rear coil end 72.
[0035] Each claw of the second claw poles 64 is located outside the
stationary yoke 4 with a small gap in between and its inner wall
faces the outer wall of the stationary yoke 4. The claw is provided
in between the first claw poles 63 circumferentially lined and
extended in the axial direction so that it is inserted into the
claw pole storing space. The second claw poles are arranged with
constant pitches in the circumferential direction. The second claw
poles 64 include an active pole portion 641 and an elongated
portion 642.
[0036] The elongated portion 642 includes wings 643 that also
functions as magnetic paths of field flux. The elongated portion
642 also includes a tube-shaped member that connects the wings 643
together. The elongated portion is located outside the stationary
yoke 4 with a small gap in between and its inner wall faces the
outer wall of the stationary yoke 4.
[0037] The frame 1 has air discharge holes 13 and 14, and an air
intake hole 15. The air discharge holes 13 and 14 are located near
the coil ends 71 and 72, and the air intake hole 15 is located on a
rear-end wall 12. The bearing 8 is fixed by partially attaching its
rear-end surface to the front-end surface of the stationary yoke
4.
[0038] The rectifier 10 is fixed to the frame 1 with a nut 31 and a
bolt 30 that penetrates the rear-end wall 12 of the frame 1. The
rectifier 10 includes a group of diodes (not shown), positive
cooling fins 2200, negative cooling fins 2300, an insulator 27, and
a terminal holder 25. The diodes perform full-wave rectification on
AC voltage outputs of the armature coil 7. Among the diodes,
positive diodes are cooled by the positive cooling fins 2200 and
negative diodes are cooled by the negative cooling fins 2300. The
insulator 27 is made of electrical insulating material. The
terminal holder 25 holds the input terminal 24.
[0039] The bolt 30 holds the negative cooling fin 23000, a middle
insulator 27, the positive cooling fin 2200, and terminal holder 25
in this order from the real-end wall 12. Then, the rear cover 200
is placed and the bolt is fixed with the nut 31 and washer 32.
[0040] The insulator 27, which is made of insulating resin,
includes the middle insulator 271 and lead-out wire insulator 272.
The middle insulator 271, substantially plate-shaped, electrically
isolates the positive cooling fin 2200 from the negative cooling
fin 2300. The lead-out wire insulator 272 is a tube-shaped member
extended from an edge of the middle insulator 271 toward the front
in the axial direction. The lead-out wire insulator 272 is inserted
into a through-hole on the frame 1. When the lead-out wire 73 is
drawn through the lead-out wire insulator 727, it is electrically
isolated from the frame 1.
[0041] A voltage is induced at the armature coil 7 by rotating the
rotor core 6 and feeding a field current to the field winding 5.
The induced voltage is applied to the rectifier 10 via the lead-out
wire 73 and rectified to a DC voltage.
[0042] The cooling fan 66 is rotated with the rotor core 6.
Therefore, cooling air currents flow through a space between the
rear cover 200 and rear-end wall 12, or a parts chamber S via the
intake hole on the rear cover 200. Then, the cooling air currents
flow into the frame 1 via the intake hole 15 and branches into the
axial direction and the centrifugal direction. The cooling air
currents that flow in the axial direction mainly flow toward the
stationary yoke 4 through a space between the claw poles 63 and 64.
The cooling air cools down the coil end 71 then exits from the
frame 1 via the discharge hole 13. The cooling air currents that
flows in the centrifugal direction cools down the coil end 72 and
exits from the frame 1 via the discharge hole 14.
[0043] The present invention produces effects discussed below.
[0044] The terminal connector 74 is crimped on the lead-out wire
73. The lead-out wire 73 and terminal connector 74 have surface
contact. Therefore, sufficient contact areas can be provided while
the plastic deformation of the armature coil 7 is maintained at
lower level. This reduces poor connection caused in severe install
conditions. This also reduces a total amount of solder or brazing
filler metal used for sufficient electrical conductance.
[0045] The solder or brazing filler metal may not be needed if
crimping portion is well designed for good electrical connection.
This reduces manufacturing cost. However, as shown in FIGS. 4 and
6, it is desirable that the space 75 is provided between the
crimping portion 741 and lead-out wire 73 for solder or brazing
filler metal. Since the solder or brazing filler metal improves
electrical conductance, a contact resistance can be reduced by
providing solder or brazing filler metal in the space. As a result,
poor connections can be reduced. Moreover, the lead-out wire 73
requires smaller space for solder or brazing filler metal than
known lead-out wires having round cross-sections. In other words,
the lead-out wire 73 requires smaller amount of solder or brazing
filler metal. Therefore, the manufacturing cost can be reduced.
[0046] The crimping portion 741 has the bottom portion 741a and
claw portions 741b and 741c. The claw portions 741b and 741c are
located at sides of the bottom portion 741a, respectively. The claw
portions 741b and 741c are bent so that they touch each other. With
the claw portions 741b and 741c, the terminal connector 74 can be
securely crimped on the lead-out wire 73.
[0047] The armature coil 7 is constructed of U-shaped segment
conductors 70. Three-phase windings are constructed by connecting
one end of the segments 70 one another after the segments 70 are
inserted into slots of the stator core 21. Therefore, the terminal
connector 74 can be crimped before the armature coil 7 is inserted
into the stator core 21. This improves flexibility in designing of
manufacturing processes. In comparison to known wave winding coil
having round cross-section, a resistance in the three-phase
windings can be greatly reduced. This reduces heat deterioration of
the solder or brazing filler metal and improves reliability.
[0048] The present invention should not limited to the embodiment
previously discussed and shown in the figures, but may be
implemented in various ways without departing from the spirit of
the invention.
[0049] A vehicle alternator shown in FIGS. 7 and 8 has axial
direction drains 210 on the outer wall of the stator core 21 for
the same number as the slots. To smooth flows of the cooling air
currents through the axial direction drains 210, a discharge hole
16 is provided more to the front than the discharge hole 13 shown
in FIG. 1. The cooling air currents generated by the cooling fan 66
flow in the centrifugal direction and cool down the coil end 72.
Then, the cooling air currents flow in the axial direction and
through the axial direction drains 210 to the coil end 71. The
cooling air currents flow through the coil end 71 in the radius
direction or toward the front while cooling down the coil end 71
and exits from the frame 1 through the discharge hole 16. By
increasing the amount of the cooling air currents around the coil
end 71, the stator 2 is cooled down more easily.
[0050] Holes may be provided in the axial direction on the stator
core 21 for the airflow instead of the axial direction drains
210.
[0051] This invention may be applied to a vehicle alternator having
brushes and field windings that rotate with a rotor.
* * * * *